Telephone system



J fi 1.935;. F. A. ROOME El AL TELEPHONE SYSTEM Filed Sept. 26, 1933 T T I T a QMQSK M23 FAROOME 'H.W.HAFFTER /N l/ENTORS ATTORNEY Patented June 18, 1935 UNITED STATES TELEPHONE SYSTEM Frank A. Roome and Hans Belgium,

ration of New York assignors to Western Electric Company, Incorporated, New

York, N. Y., a corpo- Application September 26, 1933, Serial No. 690,970 In Belgium October 21, 1932 Claims.

This invention relates to automatic or semiautomatic telephone systems and particularly to central offices in which subscribers lines are arranged in groups or classes according to the 5 character of service to which the lines in each of said classes are entitled. The object of the invention is to provide improved means for discriminating between different classes of subscribers for the purpose of restricting, blocking or passing calls initiated by calling subscribers in each of the several classes, all in accordance with the character of service allotted to each of the calling line classes.

I As is well known in present day telephone systems, there is considerable diversity in the lines of an office with respect to their class or character and the kind of service each of said classes is to be accorded. Some of the lines, for instance, may be provided with coin boxes at the subscribers stations and, in serving each of such lines, the central office automatic equipment must be provided with means for collecting the coin if the connection is completed or to return the coin if the connection is not completed. Another class of lines may involve the writing of a charge ticket by the operator to whose position said line is routed by the automatic apparatus before the call is completed; yet another class may require the automatic operation of the subscribers message register a plurality of times on a toll call requiring no ticket and completed by automatic switches, and still another class of lines may be given a so-called flat rate and in that case the switching selectors which complete the call are not required to operate the message register at all if one is provided.

At the present time the most prevalent practice in an automatic ofiice is to group all lines requiring different treatment in accordance with their respective classes and to assign a separate group of line-extending switches to each class, each of said groups of switches containing necessary means for extending, blocking or rerouting calls originated by lines in each of said groups as called for by the character of the service to which the group is entitled.

Now one of the features of this invention is a circuit arrangement for an automatic or semi- 50 automatic or like telephone system comprising diiferent classes of subscribers in which a call discriminating circuit is directly associated with line circuits of subscribers of a particular class so as to permit the use of the same kind of line-extending equipment for all classes thereby facilisubscriber S tating maintenance routines and otherwise improving the efiiciency of the central ofiice.

Another feature of the invention comprises a circuit arrangement for an automatic telephone or semi-automatic telephone system comprising 5 subscribers entitled to restricted service and unrestricted service respectively in which the subscribers of the different classes are served by the same connecting equipment and in which discrimination for calls initiated by restricted subscribers and unrestricted subscribers is determined by a digit or digits dialed.

A further feature comprises a circuit arrangement for an automatic or semi-automatic telephone system in which the class of service desired 15 by a calling subscriber is determined by means of a discriminating circuit directly associated with his line circuit. I

Another feature of the invention comprises a circuit arrangement for an automatic or semiautomatic telephone system in which subscribers line circuits are directly associated with a discriminating circuit which determines the type of call being made by the value of a digit or digits dialed.

Yet another feature comprises a circuit arrangement for an automatic or semi-automatic telephone system in which certain subscribers are provided with an auxiliary line circuit and a normal line circuit in series, the former being associated with a discriminating circuit which determines the type of call being made by the value of a digit or digits dialed and the latter being associated with the usual line-extending switches.

, A clearer conception of the scopeand purpose of the invention will be obtained from a consideration of the following description taken in connection with the attached drawing in which:

Fig. 1-A shows schematically the equipment used; and

Fig. l -B shows a discriminating circuit associated with the line circuit of a subscribers line such as that shown in Fig. 1A.

Referring, now, to Fig. 1-A, when a restricted initiates a call, an auxiliary line circuit ALC, individual to the subscribers line, is connected by a switch PR to a discriminating circuit DC. At the same time, the subscribers line is connected via the normal line circuit LC and a line finder ILF to the normal connecting equipment. One or more of the digits dialed are received by the discriminating circuit DC and are also transmitted to the exchange equipment. If the call is one to which the subscriber is entitled,

extending from ground onthetop contacts of" relay I02, subscribers loop, bottom contacts of relay I02, winding of relay IOI, battery and ground. Relay IOI closes an obvious circuit for relay I04 which, in operating, disconnects conductors I II and I I2 from conductorsl08 and I09 respectively, which latter conductors extend to the regular line circuit, and connects the former to conductors H3 and H4 respectively, which, in turn, extend to terminalsll5 and H0 of the switch I60 of-the discriminating circuit. The operation of relay IOI also completes a circuit for relay IIB extending from ground and battery through the outer contacts of relay IOI,' resistances I and I2 I, winding of relay I I8 to ground. Relay H8 operates, in 'turnoperating relay I22 which closes the circuit of all switch magnets i I1 of all idle discriminating switches, one of said circuits being from battery-through the winding of switch magnet II1 of switch I00, outer contacts of relay I22, left'outermost contacts of relay I23, back contacts of relay I24 to ground.

1 When a switch, such as switch II1, reaches the terminals of the calling line, the corresponding test relay I24 operates over a circuit extendin from ground and battery on the contacts of relay l0I, resistance I20, bank terminal I25, left Iwinding of relay I24 to ground. Relay I24 operates,-opens the circuit of switch magnet II1 thus arresting the further movement of the switch,

and closes an obvious circuit for relay I26. Relay I20 operates and closes a holding circuit for relay IN through its right win-ding and previously traced circuit to battery through the'contacts of relay IOI. Relay I26'further closes an-obvious circuit for relay I23 which latter relay, in operating, closes a circuit for relays I21 and I28 over the subscribers loop as follows: ground and bat-' terythrough the left winding of relay I28, winding of relay I21, left next-to-the-outer set of contacts of relay I23, ban-k terminal 'I I5 and cooperating switch brush, conductor 4, bottom "front contacts of relay I04, conductor H2, bottom normal contactsof relay- I03; subscribers loop, to ground on the top contacts of relay I02. Relays I21 and-I28 operate in the abovecircuit, the former closing a lockingcircuit for relay I23 and the latter closing a circuit loop for-the regular line relay I ID as follows: ground and battery through the winding of relay "I I0, bottom contacts ofrelay' I01, bankterminal I30 and cooperating brush, resistance-l3l; inner contacts "-ofrelay I28, right-inner contacts of relay I32,

bank terminal 133': and cooperating brush'to groundon the topcontacts of cut-off relay I01. Relay. I 28 further -closes an" obvious circuit for U relay 30 which', on'operating; closes'an obvious "'circuit for relay I which operates to perform The operationof' functions noted hereinafter. relay I I0 in turn energizes-thecommon start relay IBIS thereby initiating the operation-of circuitswhich' cause the connection of a line-finder and-impulse register-tothe line inthewell known manner, said line-finder and register being but schematically shown in the drawing. The connection of the line-finder switch to the line terminals then causes the operation of the regular cut-off relay I01 and auxiliary circuit cut-off relay I02 over acircuit from .ground in the linefinder' circuit (not shown), line-finder switch brush and cooperating bank terminal, winding ofv relay I01. to battery and ground and. in parallel therewith, winding of relay I02 to battery and ground. Both of these relays operate, the former causing the release of the regular line relay H0 and the latter the release of auxiliary line relay I01. Dial tone is now transmitted to the subscribers line from the register (not shown), through a line-finder brush and cooperatingbank terminal, conductor I34, terminal and brush I33, right outer contacts of relay I23, condenser I31, right inner contacts of relay I23, terminal I I6 and cooperating brush, top front contacts of relay I04, top normal contacts of relay-I03, subscribers loop bottom normal contacts of relay I03, bottom front contacts of relay I04, terminal H5 and cooperating brush, left next-to-the-outer-set of contacts of relay I23,

right middle contacts of relay I35, terminal I30 and cooperating brush, conductor I09, through a line-finder brush and bank terminal to the'tone At each impulse,

the loop to the regular exchange equipment'is opened-'at'the left inner contacts of relay I28, thus repeating the impulses forward in the well known manner. In addition, at each impulse, a

circuit is completed from ground on the back contacts of relay I28, left outer contactsof relay I35, right outer contacts of relay I32, winding of slow-release relay I39 to battery and, in parallel therewith, through the right back contacts of counting relay 164', right back contacts of countingrelay I63, right back contacts of counting relay I62, right back contacts of counting relay- IS I winding'of relay IOI to battery and ground.

Relay I6I operates and closes its contacts the left set of which looks relay IBI through the winding of relay I0! and establishes a short circuit for relay IBI over the left contacts of relay ISI, left back contacts of relay I62, conductor I,

right contacts of relay I5I, left next-to-the-inner set of contacts on relay I23'to ground on the' inner contacts of relay I21; this ground also providing'a locking ground for all other sets of counting relays. Slow-release relay I39'operatesin parallel with relay IBI so that a circuit is closed 3 forrelay I40extending from ground and battery through the winding ofsaid relay, frontcontacts of relay I39, to ground'on the left inner contacts of relay I35L' Relay I40 operates and closes itscontacts' to shortlcircuit resistance I3I' during-the forward transmission of the repeated;

impulses. When relay I39releases at the end-of the impulse of the :right digit if the digit I dialed. is a-one, groundis connected from the left inner" contacts of relay I35, back contacts of relay- I 39 ,right contacts of relay I6 I right inner back contactsof'relay I54.to.the-No. Iterminallon.

cross-connecting blockv I53;

Ifth'e digit dialed comprises two impulses, then two sets of counting relays Willbe successively operated, namely the I5I-'I6I set and the I62- IGZiset, whereupon, at the termination ofthe. impulses, the counting relays I6I and H51 will. release because theirlockin'g circuit is opened" at the left contacts of relay I62 and the ground previously traced to the right contacts of relay I6I is now extended to the right contacts ,of relay I62, left back contacts of relay I52, to the No. 2 terminal of cross-connecting block I 53. Similarly if'the digit dialed comprises three impulses, the counting relay sets I6I-I6I', I62- I62, I63--I63 are successively'operated, the sets of relays I6I--I6I', I62-I62 are released. and

the ground is extended over the front contactsv of relay I63,.left outer back contacts of relay I54 to the No. 3 terminal of cross-connecting block I53. A digit of four impulses causes counting relay. sets I6II6I', I62-I62', I63I63, I64-.I64' to be successively operated and relay sets I6I- I6I, I62- I62 and I63I63' to be released, and the ground to be extended over the front contacts of relay I64, right outer back contacts of relay I54, to the N o. 4 terminalof the above mentioned cross-connecting block while a digit of five impulses causes the successive operation of relay sets I6I-I6I to I65--I65', inclusive, the release of relay sets I6II6I' to I64-I64' inclusive, and the connection of ground over the front contacts of relay I 65, right inner back contacts of relay I52, to the No. 5 terminal of the cross-connecting block.

If the first digit consists of more than five impulses, then the sixth impulse will cause the second operation of relay I6I in a circuit extending over the right contacts of relay I65, right back contacts of relay I63, right back contacts of relay I62, right back contacts of relay I6I', winding of relay I6I to battery and ground. At the same time a circuit is closed from ground and battery through the winding of relay I54, right outer back contacts of relay I52, left front contacts of relay I65' to ground on conductor I4I. Relay I54 operates and closes a locking circuit through the winding of relay I52, left inner contacts of relay I54 to ground on conductor I4I. Relay I52 is prevented from operating at this time, however, by virtue of a short-circuiting ground through its right outer contacts and left front contacts of relay I65. When, however, the impulse is terminated, relay I6I' operates, relay I65 releases since the locking ground of relays I65 and I65 is controlled through the left contacts of relay NH, and relay I52 operates in series with relay I54; The conductors from each of the set of counting relays are now switched over the front contacts of relays I 54 and I52 from the terminals I to 5 to the terminals 6 to 0 on the cross-connecting block. Thus, for each digit from I to 0, a corresponding terminal is grounded on the left terminals of the cross-connecting block I53 and which may be suitably extended to the right terminals of said block in accordance with the character of the service characterized by said digit to the appropriate terminal on the right side of cross-connecting block I53.

If the first digit has a value which determines that the call is of the non-restricted type, the grounded terminal on the left side of connecting block I53 representing this digit is strapped to conductor I43 which, over the left back contacts of relay I45, extends to the winding of relay I46, or is strapped to conductor I 44 which is connected directly to the winding of relay 14s.

It will be observed that relay I04 has been maintained operated over a circuit extending through terminal I41 and cooperating brush, left inner contacts of relay I23, to ground on the back contacts of relay I46. The operation of relay I46 as the discriminating circuitis released in the-manner described hereinafter The line circuitis nowv is connected through the left middle, contacts of relay I35, left contacts of relay I32, terminal I46 and cooperating brush, bottom winding of relay I 03 to batteryand ground. Relay I03 operates, locks in a circuit extending from ground through its top winding and top outer front contacts, subscribers loop, bottom outer front contacts of relay I03, lower winding of relay I03 to battery and ground; operatescut-0ff relays I02 and I 0! and transmits busy tone-to the subscriber in a parallel circuit to that of relay I03 extending from ground through the left winding of the source of tone coil BT, condenser I66, bottom inner contacts of relay I03, subscribers loop and thence as traced to ground through the top :windinglof relay I03.

By the operation of relay, I03, the subscribers loop is disconnected from, the discriminating circuit which now releases as described hereinafter, busy tone is connected to the subscribers loop and the cut-oiT relays I02 and I01 are held operated. The discriminating circuit and the exchange equipment already taken into use are released.

If the value of the first digit is such that the type of service is not determined until the secondv digit is dialed and received,.then the grounded terminal on the left side of connecting block I53 denoting this class of service is strapped to conductor I50 which, over the right middle back contacts of relay I45, extends to the winding ofrelay I 5| causing this relay to operate. Relay I5I opens the locking circuit of the counting relays through its right contacts while the counting relays, inreleasing, .open the operating'circuit of relay I5I.' This relay, however, does, not .release because it is nowheld in series with relay 5'45 over a circuit fromground and battery through the winding of relay I5I and left contacts, winding of relay I45, left next-to-the-inner contacts of relay I23 to ground on the contacts of. relay I21, relay I45'being held short circuited in the meanwhile by the operating ground for relay I5I so long as the counting relays remain operated. When the counting relaysrelease, relay I45 also energizes andlocks. Relay I 45, inoperatingdisconnects conductor I43 from relay I 46, connects it to the winding of relay I32, disconnects conductor I48 from the, winding of relay I 32,,connects it to the winding of relay I46, further disconnects conductor I50 fromthe winding of relay I5I and connects it to the winding of relay I46, and short circuits relay I'5I which now releases. The impulses of the digitare now received on the counting relayseeWhen relay I39 again releases at the end of the seriesof impulses of the second digit, the ground on the cross-connecting terminal either causes the operation of relay I32 or relay I46 according tothe type of-callwhich the subscriber ismaking. If relay I 46 is operated,

3x a result of the dialingof-a digit-indicating non-, restrictedservice, releases relay I04 so that the loop to the discriminating circuit, is opened and,

transmitted thereto in the titled for transmitting a distinctive signal to said calling line, and means in said discriminating circuit responsive to the registration of said impulse series for initiating a breakdown of the partially set-up connection between said calling line and said line-extending switch.

9. In an automatic or semi-automatic telephone system, a calling line circuit equipped with an impulse sender, a relay in said line circuit, a line-extending switch, a discriminating circuit, means responsive to the initiation of a call by said line for operatively connecting said discriminating circuit to said line, means in said discriminating circuit responsive to said connection for operatively connecting said line-extending switch to said line, means in said discriminating circuit responsive to impulses transmitted from said calling line for registering said impulses in said discriminating circuit and repeating them forward to said line-extending switch, and means responsive to a predetermined series of impulses for a digit or digits indicative of a connection to which the calling line is not entitled for operating said relay to lock said calling line out of service so long as the receiver of said line is off the switchhook.

10. In an automatic or semi-automatic telephone system comprising different classes of lines, a line circuit for each of said lines, and a discriminating circuit for all of said classes capable of operable connection with any line circuit in any of said classes when an associated line initiates a call for automatically extending said line if entitled to make the call and for automatically signaling said line if not entitled to make the call.

FRANK A. ROOME. HANS W. HAFFTER. 

